This invention relates to an ink cartridge for supplying ink to a head of a record apparatus and a method of ink injection thereinto.
An ink jet record apparatus generally comprises a record head mounted on a carriage and moving in the width direction of record paper, and paper feed means for moving the record paper relatively in a direction orthogonal to the move direction of the record head.
Such an ink jet record apparatus prints on record paper by ejecting ink droplets from a record head based on print data.
A record head capable of ejecting black ink, yellow ink, cyan ink, and magenta ink, for example, is mounted on a carriage and in addition to text print in black ink, full-color print is made possible by changing the ink ejection percentage.
Thus, ink cartridges for supplying black ink, yellow ink, cyan ink, and magenta ink to the record head are placed in the main unit of the apparatus.
In the ordinary ink jet record apparatus, the ink cartridges for supplying black ink, yellow ink, cyan ink, and magenta ink are mounted on a carriage and are moved together with the carriage.
In the recent record apparatus, the carriage has been moved at high speed for the purpose of increasing the record speed.
In such a record apparatus, pressure fluctuation occurs in internal ink as an ink supply tube is extended and bent with acceleration and deceleration of the carriage, making unstable ejecting of ink droplets from the record head.
Thus, such an ink cartridge is proposed, that comprises a lower ink storage chamber (ink tank chamber) opened to the atmosphere side, an upper ink storage chamber (ink end chamber) for head connection, connected via an ink flow passage to the lower ink storage chamber, and a differential pressure regulating valve placed at midpoint in a passage connecting the upper ink storage chamber and a head supply port.
According to the ink cartridge, a negative pressure is generated on the head side by negative pressure generation means and the differential pressure regulating valve is opened accordingly for supplying ink to the record head, so that the adverse effect on ink produced by pressure fluctuation mentioned above is lessened and ink can be supplied to the record head at the optimum water head difference.
By the way, to inject ink into such an ink cartridge, the tip of an ink injector is positioned at an opening that is made in the outer surface of the ink cartridge (case) and that communicates with an ink tank chamber. Thus, in the beginning of injecting ink, the distance between the ink injection position (opening) and the bottom of the ink tank chamber is large, and also, after ink is injected (after the ink liquid level rises), there is a height difference between the ink injection position and the ink liquid level.
Thus, when ink is injected, air is easily mixed into the ink and there is a problem of bubbles occurring in the ink tank chamber.
It is therefore an object of the invention to provide an ink cartridge and a method of ink injection thereinto for making it possible to avoid air mixing into ink at the ink injection time and therefore prevent bubbles from occurring in an ink tank chamber.